Wireless communication.



C. V.-LOGWOOD.

WIRELESS COMMUNICATION. APPLICATION FILED FEB. 12. 1912.

1,161,142. Patented Nov. 23, 1915 b 21 z *2 Z 7 dz 8 WITNESSES INVENTOR W166 W090 v I I STATES PATENT OFFICE.

CHARLES V. LOGWOOD, OF PALO ALTO, CALIFORNIA, ASSIGNOR TO FEDERAL TELEGRAPH COMPANY, A CORPORATION OF CALIFORNIA.

WIRELESS COMMUNICATION.

Specification of Letters Patent.

Patented Nov. 23, 1915.

Application filed February 12, 1912. Serial No. 677,042.

To all whom it may concern:

Be it known that I, CHARLns V. Loowoon, a citizen of the United States, and a resident of Palo Alto, Santa Clara county, in the State of California, have invented certain new and useful Improvements in Wireless Communication, of which the following is a specification.

The invention relates to a receiving system for wireless communication and especially to a device adapted to be used in said system.

The. object of the invention is to provide an apparatus by means of which the electrical oscillations are caused to act directly upon an 'electro-magnetic apparatus, such as a telephone receiver or a relay, to produce sound directly from the energy of the high frequency oscillations.

Another object of the invention is to pro vide a device which when placed in the receiving circuit operates to vary the rate of charging the condenser in the telephone circuit without breaking the circuit.

Referring to the drawings; Figure 1 is a front elevation of the device of my invention mounted on and arranged to be driven by a motor. Fig. 2 is a plan or top view of the device. Fig. 3 is a diagrammatic representa tion of the receiving circuit, showing the device of my invention in place.

The receiving system comprises the aerial circuit 2 which containsv the primary winding 4, and the oscillation circuit 3, in which is arranged the secondary winding 5 and the Variable condenser 6. A telephone receiver 7 connected in shunt on the oscillation circuit is operated by the discharge of the condenser 8. Between the two condensers 6 and 8 I arrange the variable resistance device 9 of'my invention which acts to'vary the rate at which the condenser 8 is charged.

In operation theoscillations in the aerial circuit 2 produce corresponding oscillations in the circuit 3. If the oscillations in circuit 2 are continuous, and the oscillations inthe circuit 3 are in perfect resonance, the latter will obtain a fairl high voltage intensity. By varying the resistance of the circuit, the

comparatively heavy charges are accumulated during the periods of higher resistance and are discharged into the condenser 8 during the periods 'of low resistance with the result that they are sufficient to actuate the telephone receiver notwithstanding the fact that they are of high frequency. The rate of varying the resistance is comparatively high, so that the system is operable preferably with a transmission system employing continuous oscillations, but it is also operative with waves of greater damping.

The device 9 consists of a disk or cylinder 12 which is rotated at' high speed by a motor 13; The cylinder is provided with a circumferential groove 14 in which are formed. several file cut grooves 15 or similar breaks;

in the continuity of the surface. Bearing in.

this groove is a conductor, preferably in the form of a wire 16 and the resistance between the wire and the cylinder varies as the wire passes over the irregularities in the groove- Instead of having transverse ridges or grooves on the cylinder, a rough circumferential groove may be formed thereon, the irregularities of the surface of the groove being sufficient to produce the desired variations in resistance.

The wire 16 is clamped to an arm 17 which is secured to block 18 which is keyed to a bar 19 mounted on the back plate 22 which is formed of an insulating material. The block 18 is held in position longitudinally on the bar 19 by the set screw 23. Attached to the upper side of the block 18 is an arm 24 in which is arranged an adjusting screw 25 which bears against the arm 17. This arm is flexible, so that the screw 25 may be turnedto adjust the pressure of the wire 16' I claim 4 1. In a receiving system for W113 less communication, a device for varying t e res1stance of the local circuit, without completely.

interrupting the same, comprising a high velocity rotating cylinder having a slightly irregular surface and a flexible conductor contacting with said'surface, said conductor and cylinder being in series in the local circuit.

2. In a receiving system for Wireless communication, a device for varying the resistance of the local circuit, without completely interrupting the same, comprising a high velocity rotating cylinder having a rough surfaced circumferential groove therein, a flexible conductor bearing in said groove, and means for adjusting the pressure of contact between the conductor and the cylinder.

3. In a receiving system for Wireless communication, a local circuit, a resistance varying device arranged in said circuit, said device comprising a high velocity rotating broken surface, a conductor bearing on said surface, and means for varying the pressure 1 of said conductor on said surface.

In testimony whereof, I have hereunto set a my hand at San Francisco, California, this 7th day of February 1912.

CHARLES v. Loowooii In presence of- H. G. Pnosr, R. HEFIERMAN. 

